Terminal Velocity

There's a bit of a lull in the fires here at work, so I was reflecting back on a conversation I had with someone (I don't actually remember who) about terminal velocity, and there was a lot of misinformation from their side.

Early in the conversation they mentioned the experiment that Galileo performed, and that the feather fell at the same rate as the ball. This is a common misconception; the experiment featured no feather (that was David Scott on the Apollo 15 moon landing), but a great illustration of the misunderstanding of terminal velocity.

Before I begin, it's worth defining the term. Terminal velocity is the maximum speed an object can reach under given conditions.

Firstly, it's important to understand that the presence of gravity (and it's effect) does not imply terminal velocity. Terminal velocity is achieved when the ACCELERATION due to gravity (32 meters/second²) is balanced by the RESISTANCE of the substance the object is falling through. Most of the time, that's air.

So, say a feather and a baseball are dropped from a hot air balloon. As they start to fall, they will both accelerate at a rate of ~32m/s² (apprx due to distance from center of Earth), but their rate of acceleration will immediately begin to decrease as they air they are falling through applies its resistance. Surface area and shape play a huge role here as well; the ball's acceleration will decrease slowly due to its more aerodynamic shape, whereas the feather will rapidly cease to accelerate and start to flutter.

This is where it starts to become obvious that there is no universal "Terminal Velocity." An even more compact example is a sky diver with a winged suit. Wings in, the sky diver has less surface area and a higher terminal velocity.

But, what happens when an object isn't falling through a substance? This is where we head back to the moon. Dr. Scott was in, more or less, an environment void of atmosphere; anything he dropped would be exposed to negligible external resistance, and so would be at the mercy of gravity alone. And he tested it. When he dropped a hammer and a feather they accelerated at the same rate throughout their decent and landed simultaneously.

To pull things back a bit farther; that baseball from the hot air balloon would hit a certain speed and stop going faster; that is, it would reach a terminal velocity. If Dr. Scott could have gotten further away from the surface of the moon before he dropped his items, that feather and hammer would have hit the moon going limitlessly fast. Well, limitless until you consider the gravitational pull of the Earth, the realistic distance at which the moon would apply its gravity and the strength thereof (bear in mind, the acceleration due to lunar gravity is only 1.6 m/s²)... so, you know, "nearly headless."

The Conversion

To begin, for those who haven’t heard, I ended my 6.5 year career at Nintendo at the end of May. We parted on good enough terms, and over this first week of transition I’ve even exchanged a few emails to help with projects I left behind. Where did I go? Well, not too far at all, actually! I went from one of the oldest entertainment companies in Japan to one of the oldest entertainment companies in America; I’m now working for Disney, albeit as a contractor for now.

But this post isn’t about that. No, this post is about a lack of communication, a change in the status quo, and what it means to me personally.

It begins with the miscommunication, as these stories generally do; no one ever asked me when I started what sort of computer I wanted. I didn’t even think to mention it as every IT shop in the world runs Windows, right?

Well, that’s apparently where the change in status quo comes in. For the last year, nearly every employee my new manager has hired has wanted a Mac, and sixth months ago he decided he was sick of getting a PC, then needing to put in a request for hardware, then wait 2 weeks, and then have more down time while the employee sets up the new Mac. So, he just started defaulting to it.

And me? I never asked, so here I am, telling you about my first week… from a Macbook Pro. And let me tell you, I’m definitely seeing why folks want this setup.

First of all, it’s cheating. I didn’t have to choose between Windows and OSX; I get both via Parallels, so if something is easier/better in Windows, I just hit ⌘Tab and go to town. While I’m there, Option + Tab serves as Alt - Tab, and hitting ⌘Tab again brings me right back out to OSX for what I’ve found it does best.

And that is command line. Back when Mr. Jobs & Company changed from OS9 to OSX, dropping PowerPC, signing up Intel, and swapping the core of the OS over to a Unix-based platform, I was just graduating High School. In college and beyond, I never used a Mac again, but I did use Linux. And now I’m glad I did; there’s some real power in the CLI on OSX.

All that said, however, there is one thing I’m still getting used to. OSX makes it much harder (natively) to maximize windows, dock them to the sides of your screen, and do other “structured” operations with windows, which I thought was odd at first. As I’ve used it, however, I’ve realized that maybe I’M the one who’s been doing it wrong.

I’ve started letting windows take up their minimum space, and letting the screen naturally fill with tasks, ebbing and flowing as my day goes. The Parallels window breaks the flow a bit (as having a 1/8 screen VM isn’t all that useful), but otherwise it’s been enlightening.

So far, I haven’t found anything that’s dramatically harder or easier between the two platforms. Finding some software for OSX ( e.g., a specific version of the JDK from 1.6) has been challenging at times, but most of it is from the era before the change in the quo.

In all, I like the change for getting things done. However, it’ll be a while before I drop my native Windows OS machine due to hardware costs and software (game) support. Apple is getting close, though, and this experience has gone a long way in convincing me of that.